Browsing by Author "Cui, Linfan"

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  • MXene-Polymer Hybrid for High-Performance Gas Sensor Prepared by Microwave-Assisted In-Situ Intercalation
    (2022-09) Zhou, Jin; Hosseini Shokouh, Seyed Hossein; Komsa, Hannu Pekka; Rieppo, Lassi; Cui, Linfan; Lv, Zhong Peng; Kordas, Krisztian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    2D transition-metal carbides (Ti3C2Tx MXene) intercalated with organic molecules have been widely used in batteries and supercapacitors, but are quite rarely reported for gas sensing. Since Ti3C2Tx is sensitive to oxygen, most methods for preparing the intercalated Ti3C2Tx involve stirring the reactants with Ti3C2Tx for several hours under nitrogen protection. Herein, a method to prepare a hybrid of Ti3C2Tx and intercalated polysquaraine through microwave-assisted in situ polymerization that takes only a few minutes without the need of using a protective atmosphere is demonstrated. Owing to the increased interlayer space of the Ti3C2Tx after the polymerization, the gas sensors based on the hybrid exhibit a good sensing performance for NH3 detection, being able to detect at least 500 ppb NH3 with a 2.2% ppm−1 of sensitivity. This study provides a facile preparation method for developing intercalated MXenes, which are expected to be useful for a wide range of applications.
  • Recent developments of electrodeposition-redox replacement in metal recovery and functional materials: A review
    (2023-06-01) Cui, Linfan; Yliniemi, Kirsi; Vapaavuori, Jaana; Lundström, Mari
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    One way to overcome the complex problem of the increasing demand for metals coupled with the rapid depletion of high-grade raw materials is to boost research into innovative methods of metal recovery. Electrochemical recovery for metal production has already gained ground in the electrowinning and electrorefining of Cu, Zn, and Au, for example, from highly concentrated and purified hydrometallurgical solutions. Since 2015, an electrochemical technique, based on the combination of the electrodeposition (ED) and redox replacement (RR) processes, has been developed in the context of trace metal recovery (μg/L – mg/L). Specifically, EDRR enables the efficient recovery of precious metals, including Ag, Au, Pt, and Te, from underutilized secondary raw materials-hydrometallurgical solutions, where these metal species are naturally present. With highly flexible electrochemical process parameters, EDRR also allows controllable preparation of metal coatings, nanoparticles, and even functional surfaces directly from lower-grade resources, further indicating the promise of EDRR to relieve material scarcity. In this review, we analyze in detail the significant progress regarding EDRR for both metal recovery behavior and creation of high-value-added materials. The future prospects for EDRR, including energy efficiency and sustainable materials, are also outlined.
  • Two-dimensional MXenes for lithium-sulfur batteries
    (2020-07) Zhang, Chuanfang (John); Cui, Linfan; Abdolhosseinzadeh, Sina; Heier, Jakob
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    Rechargeable lithium-sulfur (Li-S) batteries have attracted significant research attention due to their high capacity and energy density. However, their commercial applications are still hindered by challenges such as the shuttle effect of soluble lithium sulfide species, the insulating nature of sulfur, and the fast capacity decay of the electrodes. Various efforts are devoted to address these problems through questing more conductive hosts with abundant polysulfide chemisorption sites, as well as modifying the separators to physically/chemically retard the polysulfides migration. Two dimensional transition metal carbides, carbonitrides and nitrides, so-called MXenes, are ideal for confining the polysulfides shuttling effects due to their high conductivity, layered structure as well as rich surface terminations. As such, MXenes have thus been widely studied in Li-S batteries, focusing on the conductive sulfur hosts, polysulfides interfaces, and separators. Therefore, in this review, we summarize the significant progresses regarding the design of multifunctional MXene-based Li-S batteries and discuss the solutions for improving electrochemical performances in detail. In addition, challenges and perspectives of MXenes for Li-S batteries are also outlined. image
  • An ultra-sensitive NH3 gas sensor enabled by an ion-in-conjugated polycroconaine/Ti3C2Tx core-shell composite
    (2023-06-01) Zhou, Jin; Hosseini Shokouh, Seyed Hossein; Cui, Linfan; Järvinen, Topias; Pitkänen, Olli; Lv, Zhong-Peng; Kordas, Krisztian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    MXenes are emerging sensing materials due to their metallic conductivity and rich surface chemistry for analytes; they, however, suffer from poor stability. Incorporation with functional polymers can largely prevent the performance decay and enhance the sensing performance. Herein, we demonstrate a core-shell composite, Ti3C2Tx@croconaine (poly(1,5-diaminonaphthalene-croconaine), PDAC) prepared by a facile in situ polymerization reaction, suitable for NH3 detection. Compared to pristine Ti3C2Tx, the sensor made of a Ti3C2Tx-polycroconaine composite exhibits a significantly enhanced sensitivity of 2.8% ppm−1 and an estimated achievable limit of detection of 50 ppb. The improved sensing performance could be attributed to the presence of PDAC facilitating the adsorption of NH3 and changing the tunneling conductivity between Ti3C2Tx domains. Density functional theory (DFT) calculations reveal that the adsorption energy of NH3 on PDAC is the highest among the tested gases, which supports the selectivity of the sensor to this analyte. Benefiting from the protection conferred by the PDAC shell, the composite has a reliable operation period of at least 40 days. In addition, we demonstrated a flexible paper-based sensor of the Ti3C2Tx@PDAC composite, without attenuated performance upon mechanical deformation. This work proposed a novel mechanism and a feasible methodology to synthesize MXene-polymer composites with improved sensitivity and stability for chemical sensing.